Robot grippers are used to grip and move articles. Two armed robots attempt to grip and lift articles with the center of gravity of the article located in a center position between the arms. Robot grippers, however have difficulty in holding heavy or long articles with stability. Robots that are used to grip an article in industry, may cause an accident by slipping and dropping the article. Therefore it was necessary to develop a method that can determine stability during gripping, such as by using a sensor while gripping in order to preclude such an accident.
KR10-2012-0069923 A, titled “WALKING ROBOT AND METHOD FOR CONTROLLING BALANCING THE SAME” discloses a walking robot and a method for controlling balance of the robot for controlling the stable balance of a walking robot that operates the joints with a torque servo. It is possible to keep an erect posture and a desired upper body angle even under external changes including any force form the outside and the degree of inclination of the ground, by calculating virtual gravitational acceleration, using the centers of gravity of a robot, and calculating gravitational compensation torque for applying a force to a link from the calculated virtual gravitational acceleration. Further, a robot can keep the erect posture with respect to the gravitational direction even under conditions without information about the inclination direction and the degree of inclination of the ground, and can keep the posture of the upper body and the legs stable while changing the angles of the ankle joints even if the ground where the robot stands gradually inclines. However, it was difficult to evaluate the stability in gripping an unknown object even using the method, therefore such a technology is necessarily required for the robots in the industrial fields.
The description provided above is a related art of the present disclosure for helping understanding the background of the present disclosure.